Fork lift truck with boom



Jan. l0, 1950 R, BUCKSATH 2,493,750

FORK LIFT TRUCK WITH BOOM Filed Feb. e, 1948 IN V EN TOR.

WWM

Patented Jan. 10, 1950 amaro l ronx mer 'nwcx wrrn nooM RussellBucksath, deceased, late of Long Beach, Calif., by Grace Bncksath,administran-ix, Long Beach, Calif.

Application February c, 194s, serial No. 6,510

e calms. (ci. 214-95) (Granted under the act oi' March 3,1883, asamended April 30, 1928: 370 0. G. 757) The invention described herein,if patented. may be manufactured and used by or for the Government forgovernmental purposes, without the payment of any royalty thereon.

This invention relates to a fork lift truck with a boom', and moreparticularly, to a lift truck of conventional commercial design,convertible into a derrick or crane by a removable boom or outrigger.

Fork lift trucks have found wide acceptance in warehousing operations;and it is possible, by employing them, to stack, load, or otherwise movegreat quantities of matriel in a comparatively small amount of time andwith a great saving in man power. However, the type of matriel which canbe processed by means of the conventional fork lift truck is limited toarticles of comparatively small or medium size, as the forks of the lifttruck are unable to support a large article, e. g., an article twice thesize of the forks. Also.

. the operational range of a conventional fork lift truck is limited toremoval of matriel from floor level to an elevated level and vice versa,but does not reach levels below the floor level; for instance, it is notpossible to load or unload a barge with a fork lift truck standing on anelevated pier.

It has been proposed to remedy these shortcomings of a conventional lifttruck by mounting on its forks or other load-supporting means a boom oroutrigger, carrying at its free end a hook or other load-supportingmeans, whereby the fork lift truck is converted into a wheeled derrickor crane. Examples of such industrial trucks are shown in U. S. PatentNo. 2,364,493, Ulinski, and French4 Patent No. 748,739, Fenwick S. A.These devices consist of conventional industrial lift trucks, andremovably mounted at or near the free end of the load-supporting surfacea pivoted Outrigger terminating in a hook. Although well adapted toaccomplish the objects for which they are intended, these devicespossess certain disad- 2 industrial fork lift truck in enabling theoperator of the lift truck to install the same without help or tools.

Still another object of this invention is a combined industrial lifttruck and boom, which can in a small parking space without the need ofrevantages which this invention overcomes, and

which are readily apparent by comparing them with the preferredembodiment of this invention.

Accordingly, it is an object of this invention to provide an attachmentfor an industrial lift truck of strong and lightweight construction, andwithout movable parts, capable of converting the moving the attachment.

These and other objects and advantages of the present invention, notpresent in the prior art, will become more readily apparent through thefollowing description of a preferred embodiment of the invention,illustrated in the appended drawing.

In a fork lift truck with boom, according to the present invention, aconventional industrial fork lift truck is equipped with a boom having aloadsupporting device such as a hook at one end and carrying a pair ofspaced brackets at its other end, which are threadable over the freeends of the forks and slidable over substantially the entire horizontallength of the forks.

In the appended drawing, which illustrates a preferred em?. udiment ofthe invention, y

Figure l is a schematic view of a fork lift truck with boom in operativeposition and engaged in the loading of a barge from a raised pier;

Figure 2 is a perspective view of a fork lift truck and boom inassembled relation, the truck being shown in part only;

Figure 3 is a front elevation of a boom attachment in accordance with myinvention; and

Figure 4 is a side elevation of the boom attachi ment corresponding toFig. 3, and showing the attachment in inoperative (full lines) and inoperative (broken lines) position.

More particularly, reference numeral I0 indicates the body of anindustrial lift truck, equipped with an upright Il, whereon is mountedin verti cally slidable relation a load-supporting device I2, comprisingin the illustrated device a pair of substantially L-shaped forks I3,I3', the horizontal tines of which extend forwardly of the truck bodyI0. It will, of course, be understood that such a lift truck isconventional and well known to the art, and is not claimed by me assuch, other than in combination with the boom attachment plished by theaforementioned attachment of an hereafter described. The said boomattachment,

apex of the triangle is provided a hook I1 adapted to support a load I8by means of a sling I9 or equivalent means; the hook Il may be fixed inplace (as shown in the drawings) or conventionally supported from ahorizontal shaft or trolley (not shown) associated with the free ends ofthe boom at the apex of the triangle. At the base of the boom is a pairof brackets 20, 20".

asmuch as equivalents of specific details described parts will readilyoccur to the expert, which equivalents are thus desired to be embracedwithin the scope of the present invention, the latter is intended to belimited only by the appended claims.

Itis claimed:

l. In combination with a lift truck of the type comprising a vehicle, anupright extending from said vehicle, and projecting load-supportingmeans slidably associated with said upright: a

spaced from each other for distance equal to the space between forktines Il, I3'. Each bracket is of sumcient width to permit the insertionof a tine (I3, or I3') into the bracket and to permit a pivotal orrocking motion of the boom relative to the fork, when the boom rests onthe fork, while at the same time holding the boom against lateraldisplacement from the fork. Cable means 2l extend from the apex of thetriangle to the vertically slidable load-supporting means I2 at a pointor points above the horizontal portion of fork I3, I3', so as to holdthe boom in angular relation to the upright I I of truck I0.

When it is desired to assemble lift truck and boom, the following stepsare performed: The fork of the lift truck is lowered, cable means 2Iextending from the apex of the boom are fastened in place to thevertically sliding portion I2 of the truck by suitable means e. g., snaphooks 22, and the free ends of tines I3, I3' are inserted into brackets20, of the base I6 of the boom. Finally, the base of the boom is slidtowards the body I0 of the truck until base I6 abuts on the ends of thetines I3, I3' proximate the upright I I. In this manner, a iirmly bracedOutrigger structure is obtained, which is able to support loads of.considerable magnitude. As load I8 exerts a downward pull at the apexof the boom triangle, it tends to urge the base end of the boom to adirection opposite the free ends of the tines I3, I3' of the lift fork;thus, as base I6 of the boom acts as a bearing surface at or near thebase of the fork, it eliminates the undesirable shearing effect on thetines which would result if the boom were supported on the fork at ornear the-free ends of the tines. By selecting cable means 2l of suitablelength, the angle between the boom and the upright can-be adjusted so asto elevate or depress the boom to the desired position.

When it is desired, after assembling lift truck and boom, to use theforks of the truck rather than the boom itself, it is not necessary toremove the boom. In such a case', the boom is tilted upwardly toayertical or nearly vertical position (as shown in Fig. 4 in full lines)and held in place by appropriate means, e. g., by insertion of bolt 22associated with sliding portion I2 intoeye 23 on boom Il. This leavesthe horizontal portions of the fork unobstructed and permits them toengage loads in the same manner as if `the boom were removed from thetruck.

-In the foregoing description of a fork truck with boom inaccordancewith the present invention has been illustrated theconstruction and operation of a preferred embodiment of the same.However, it will be understood, of course, that it is not intended tolimit the scope of the invention to any specic structural details, asfor instance, the triangular shape of the boom or other detailsdesirable but not essential for its operation. In-

boom adapted to support a load from one end, a

bearing surface proximate the other end of said boom for pivotalabutment on said load-supporting means, means removably positionable onsaid load-supporting means and adapted to hold said bearing surface inpivotally abutting engagement with said load-supporting m'eans proximatesaid upright and preventing lateral displacement of said boom, and meansfor holding said boom in angular relation relative to said upright.

2. In combination with a fork lift truck of the type comprising avehicle, an upright extending from said vehicle, and a projectingload-supporting fork having spaced tines, said fork being slidablyassociated with said upright: a boom adapt ed to support a load from oneend, a bearing surface proximate the other end of said boom adapted topivotally abut on said tines, spaced bracket means loosely interiittingwith and removably positionable on said tines to hold said boomproximate said upright and against lateral displacement, and means forholding said boom in angular relation relative to s aid upright.

I 3. A boom removably positionable on projecting load-supporting meansof a lift truck, said boom comprising an isosceles triangle, meansproximate the apex of said triangle for supporting a load, and meansopposite the apex of said triangle for removably positioning said boomon said loadsupporting means, said means comprising a bearing surface atthe base of said triangle pivotally abutting on said load-supportingmeans, and bracket means associated with said bearing surface andloosely interiitting with said load-supporting means.

4. A boom removably positionable on the projecting tines of a fork lifttruck, said boom comprising an isosceles triangle, means proximate theapex of said triangle for supporting a load, and means proximate thebase of said triangle for removably positioning said boom on said tines,saidl means comprising spaced brackets loosely interiitting with saidtines.

5. A boom removably positionable on the projecting tines of a fork lifttruck, said boom comprising an isosceles triangle, means proximate theapex of said triangle for supporting a load, a bearing surface at thebase of said triangle adapted to pivotally abut on said tines, andspaced means at said base removably positionable on and looselyinteriitting with said tines to prevent lateral displacement of saidboom relative to said tines.

6. In combination: A fork lift truck of the type comprising a vehicle;an upright extending from said vehicle; a projecting load-supportingfork slidably associated with said upright and having spaced tines; aboom comprising a pair of convergent beams, load-supporting means at theapex of said boom, and spaced bracket means on the opposite end of saidboom, said bracket means interiitting. loosely with said tines andremovably'and pivotably supporting said boom on said tines proximatesaid upright; and means for 5 holding said boom in angular relation toldd u r ht.

p is Number UNITED sTATms PATENTS GRACE BUcxsATH. Name Date Adminmratrixof the Estan of Rama Buck- ,1.837.486 Remde Dec- 22. 1931 ,am Deemed, 5,2.381.744 Clapp oct. so, 1945 2,433,584 Turner Dec. so, 1947 REFERENCES,CITED v FOREIGN PATENTS The followin references are of record in theNumber Country Da me of ms wint: 1 '148,139 mm Apr. 25, 1m

